8721440 has 96 divisors (see below), whose sum is σ = 25401600. Its totient is φ = 2755584.

The previous prime is 8721413. The next prime is 8721443. The reversal of 8721440 is 441278.

8721440 is digitally balanced in base 5, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (26).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8721443) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14261 + ... + 14859.

It is an arithmetic number, because the mean of its divisors is an integer number (264600).

Almost surely, 2^8721440 is an apocalyptic number.

8721440 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 8721440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (12700800).

8721440 is an abundant number, since it is smaller than the sum of its proper divisors (16680160).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

8721440 is a wasteful number, since it uses less digits than its factorization.

8721440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 634 (or 626 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 26.

The square root of 8721440 is about 2953.2084247476. The cubic root of 8721440 is about 205.8398226995.

The spelling of 8721440 in words is "eight million, seven hundred twenty-one thousand, four hundred forty".